This invention relates to bipolar transistors in integrated circuits and, more particularly, to a bipolar transistor with improved collector to emitter breakdown voltage while maintaining a high beta.
Advanced automotive, consumer and industrial applications are driving integration of power, Ultra High Voltage Complementary Metal Oxide Semiconductor (UHV CMOS) and bipolar analog functions with microcontrollers and embedded non-volatile memory. Hyperintegration technology (MOTOROLA, INC. technology) is based on a Complementary Metal Oxide Semiconductor (CMOS) platform and integrates power, bipolar devices with EEPROM and flash Electrically Erasable and Programmable Read Only Memory (EEPROM). This technology provides an integrated system solution for automotive electronics applications such as airbags, power window and power seat modules. Bipolar transistors in the Hyperintegration technology are used primarily in the input/output ports and the voltage regulator circuit. However, because of the integration and the reduction in size of the various components, process induced variations in the various components are relatively common. Also, the collector to emitter breakdown voltage (BVCEO) is usually much less than the collector to base breakdown voltage (BVCBO) and it is desirable to have the BVCEO approach or equal the BVCBO.
It is highly desirable to provide apparatus which overcomes these problems by minimizing process induced variations and improving the BVCEO while maintaining efficient area usage and which is inexpensive and easy to install and use.
A primary purpose of the present invention is to integrate a stable, low-cost bipolar transistor in a conventional CMOS process.